a. Technical Field
The present invention relates to a communication device which performs an exchange of information between its own communication unit and one or more other communication units.
b. Prior Technology
(1) The conventional network connects devices installed in specific locations or desk-top units by means of wire communication means and both the component devices of the network and the users who use the connected devices are fixed. This network includes service providing devices which provide specific services in response to the users' requests.
The service providing device includes a shared data file service providing device, a kana-kanji conversion service providing device, a dictionary service providing device, a voice recognition service providing device, and a translation service-providing device, among others. In each service, a communication link between the client and the service providing device is first established on reception of a request for the service, the relevant processing is performed, the result of the processing and the information representing completion of the service are transmitted to the client through said communication link, and the communication link is canceled on completion of the service.
The service providing device which delivers the result of processing includes a shared data management service providing device, a kana-kanji conversion. service providing device, a dictionary service providing device, a voice recognition service providing device, and a translation service providing device, among others. On the other hand, a voice synthesis service providing device and a printer service providing device, among others, are service providing devices which do not deliver the result of processing.
In the conventional network, since it is pre-determined which device performs a given service and the data are registered in the respective devices connected to the network, the user requesting a service can obtain an automatic connection to the device which provides the requested service based on the data registered in his own terminal device. Moreover, where a plurality of devices capable of providing services are present on the network, concentration of the load on any specific one of them can be avoided by insuring that the load will be evenly distributed among them through variation of registered data for the respective users.
The registration of data can only be made by a specific manager and, therefore, in order to add or change the service providing device, the general user has to request the manager to that effect. However, the above scheme of registering data in the respective devices calls for updating of the data in each device whenever a change of the service providing device has taken place and this imposes a burden on the user. In order that change of the network structure and change of service providing device can be made with good flexibility, a method is utilized which comprises resistering network structure data and service providing device data in a specific device connected to the network and the other devices are down-loaded with the data at initializing after power-on at the respective terminals. In this arrangement, as the information in the manager device is updated, each terminal device is enabled to request a service based on the change so made, with the result that savings can be realized in management time.
Recently with advances in hardware technology, the capability of portable devices has been increased to the level of the earlier desk-top terminal devices. In addition, radio communication means which takes the place of wire communication means have become available. Whereas the location of use of devices was confined in the past, such portable devices and radio communication means have enabled the user to move about carrying such a portable device and have access to the network from where he is currently located by utilizing the radio communication means.
Under the circumstances, the requirements of a network have also changed, so that a demand has emerged for greater flexibility of the network structure.
To meet the above demand, the present applicant previously proposed a new communication control apparatus and a new method for communication control utilizing radio communication means (Japanese Patent Application No. H-6-75757).
According to this proposed technology, a network can be constituted and communications be made with any desired party in any desired place by mere bringing together of the terminal devices. In this technology, a network can be established whenever necessary and be erased when unnecessary. Moreover, it is possible to add a device to the network or withdraw a device from the network, thus enabling a flexible operation of the devices.
(2) Recently, a technology has been proposed in which a plurality of communication devices on the network share the same data for collaborative work. This is a technology such that in cases where word processor document data are shared, for instance, change of the data by any one user results in the simultaneous change of the document data for the other users.
By connecting a plurality of communication devices through a logical communication link and making transmission of data in a multiple-address way to the communication devices connected to said logical communication link, a personal data can be distributed to a plurality of persons. Moreover, a change of data which occurred in a specific communication device is also reported in a multiple-address way to all the communication devices through said logical communication link and data updating is made in every communication device. In this arrangement, data can be shared by a plurality of communication devices. The term "logical communication link" is used herein to mean a connection of a plurality of mutually communicable communication devices demanding communications into a group without the user needing to take any special procedure.
In a collaborative work such as a conference or a collaborative writing of documents, there is not only the case in which the participants gather together at one time but also the case in which a new comer joins the collaborative work. In the latter case, the data currently shared has to be distributed to the new comer's communication device.
The sequence of distributing the shared data to a new communication device is now described with reference to the flow chart shown in FIG. 18. It is assumed that there are communication devices A, B, C and D which are connected through a logical communication link M, carrying the same data, and engaged for a collaborative work using said data, that the communication device B has been chosen as a coordinator or responding communication device, and that a communication device E not connected to said logical communication link M has made a connection request.
(Step k1)
As a new request for connection is received, the communication device that is to respond to the request is selected in the first place. When shared data are dispersively managed by the respective communication devices, a certain conciliation is made among the participants before starting a collaborative work or at starting an application and a specific communication device which is to assume this role is determined beforehand. When the collaborative work is a conference, for instance, the communication device which is to act, so to speak, as a chairman who presides over the conference is first selected.
The setting so established remains unaltered till the end of the conference except for cases in which the chairman withdraws himself partway in the course of the conference or a trouble occurs in the communication link.
The respective communication devices are then connected with the main logical communication link M and the data possessed by the respective individual devices are mutually distributed for sharing.
(Step k2)
Communication device E which is not connected to said main logical communication link M accesses the communication devices A, B, C and D on the logical communication link M through a control link which is communicable with all the communication devices to transmit a message requesting participation in the work.
(Step k3)
When each of the communication devices A, B, C and D has received the above-mentioned message, the communication device designated as the coordinator or responding communication device establishes a new sub-logical communication link N with communication device E through said control link.
(Step k4)
The communication device B then distributes the data already shared to the communication device E.
(Steps k5 and k6) After distribution of the shared data, the sub-logical communication link N is erased and the communication device E is added to the main logical communication link M.
The distribution of shared data to a new communication device making a connection request is normally carried out in the above manner. However, in cases where the communication device B has defaulted for some reason or other or a trouble has occurred in the communication link to the communication device B when a new comer communication device makes a connection request, the request is not accepted.
Moreover, at the communication devices other than the coordinator device, the status of data distribution cannot be ascertained so that it was difficult for the participants in the collaborative work other than the coordinator B to confirm whether the data has been distributed to the new comer.
Furthermore, in the event that, when the communication device B is setting a sub-logical communication link N to communication device E and distributing the shared data, a message requesting data sharing is received from a new communication device F, either the new request must be caused to stand by until completion of the data distribution to communication device E or a separate process has to be started to establish a new logical communication link L to the communication device F. Thus, in the prior art, one communication device has to respond severally to requests from a plurality of communication devices.
(3) Recently with the spread of portable data communication devices which can be freely relocated, a need has arisen to couple them electronically for exchange of data. In this case, it is necessary to designate the other party's communication device. As a typical method, a number specific to the communication device is designated. However, in this case, there is the problem of discrepancy from the actual topological relationship.
(4) Furthermore, when editing is carried out for data on a certain subject matter or for information relevant to such data using a plurality of communication devices, it is a usual practice to store all or part of said data in the memories of the respective communication devices. The users edit and process the data stored in their respective devices independently and after completion of the editing, the results are consolidated.
The disadvantage of this method, despite sharing of the data stored in the respective communication devices, is that since each user performs editing and processing independently of the other users, no consistency can be obtained in the whole information stored among the respective communication devices.
In order to assure a consistency of data shared by a plurality of communication devices (hereinafter referred to as shared data), a system is known in which each communication device is provided with communication means and shared data managing means for assuring such consistency of data. Thus, when the shared data stored in a given communication device has been altered by user input with respect to the shared data in the memories of the communication devices, shared data change information is transmitted by said communication means to the other communication devices and using the shared data change information received from any other communication device, the shared data memorized in the communication device is updated by said shared data managing means.
Communication devices of the above type are in use as a collaborative documentation system or a teleconference support system.
However, with such communication devices, the display area data for the displays of the respective communication devices cannot be correlated among the devices for controlled output at each communication device.
Therefore, an output based on display area information such as "Display the page following page X of the document data on display at other communication device Y" cannot be generated at any given communication device.
With regard to input, too, it is impossible to correlate the user input display area data among a plurality of communication devices and accept the user input at the respective communication devices according to the correlation information.
In other words, it is impossible to perform an input processing for other communication devices through the input means of a given communication device.
The above problem is particularly pronounced when a plurality of communication devices are installed close to each other, a plurality of users sit face to face, and each user operates either one or more of the communication devices for exchange of data and shared data.
Specifically, if one user could point to this or that on the displays of other users' communication devices through the input means of his own communication device, all the users should easily understand what is meant.
However, in the above arrangement, it is necessary for one user to output the same data as the output of the other user at his own communication device and, then, enter an input so as to have "the message he entered" displayed on the display of the other user's device to point out "the change of shared data" and thereby cause the other user to understand the change.
However, the degree and speed of understanding by the other user are inferior to those available by direct pointing. Moreover, for the user who does pointing, too, he must focus his attention on manipulation on his own communication device, rather than on transmission of the message to the other user.
Therefore, it is impossible to take advantage of the otherwise efficient communication intrinsic to the situation that each of the users sitting face to face can ascertain what the other user or users are viewing, with the result that each of the users forces the other users to tolerate inefficient communications.